{
  "type": "FeatureCollection",
  "features": [
    {
      "stac_version": "$${env('stac_version', '1.0.0-rc2')}",
      "stac_extensions": [
        // skip SAR sensors
        "$filter{eop:parentIdentifier LIKE 'SENTINEL%' or eop:parentIdentifier LIKE 'LANDSAT%'},https://stac-extensions.github.io/eo/v1.0.0/schema.json",
        "https://stac-extensions.github.io/view/v1.0.0/schema.json"
      ],
      "id": "${eop:identifier}",
      "type": "Feature",
      "geometry": "${footprint}",
      "bbox": [
        "$${minx(footprint)}",
        "$${miny(footprint)}",
        "$${maxx(footprint)}",
        "$${maxy(footprint)}"
      ],
      "properties": {
        "start_datetime": "$filter{timeStart is not null and timeEnd is not null and timeStart <> timeEnd},${timeStart}",
        "end_datetime": "$filter{timeStart is not null and timeEnd is not null and timeStart <> timeEnd},${timeEnd}",
        "datetime": "$filter{timeStart is not null and (timeEnd is null or timeStart = timeEnd)},${timeStart}",
        "created": "${eop:creationDate}",
        "updated": "${eop:modificationDate}",
        "platform": "${eop:productPlatform}",
        "instruments": "${eo:collection/eo:instrument}",
        "constellation": "$${strToLowerCase(eop:parentIdentifier)}",
        "eo:cloud_cover": "${opt:cloudCover}",
        // "view:off_nadir": "${opt:instrumentElevationAngle}",
        // "view:incidence_angle": "${opt:incidenceAngle}",
        // "view:azimuth": "${opt:instrumentAzimuthAngle}",
        "view:sun_azimuth": "${eop:illuminationAzimuthAngle}",
        "view:sun_elevation": "${eop:illuminationElevationAngle}",
        "sar:instrument_mode": "$filter{eop:parentIdentifier = 'SENTINEL1'},WV",
        "sar:frequency_band": "$filter{eop:parentIdentifier = 'SENTINEL1'},C",
        "sar:center_frequency": "${sar:dopplerFrequency}",
        "sar:center_frequency": "${sar:dopplerFrequency}",
        "sar:polarizations": "${sar:polarisationChannels}",
        // should be an array, what to do here?
        "sar:product_type": "$filter{eop:parentIdentifier = 'SENTINEL1'},GRD",
        "sar:observation_direction": "$${strToLowerCase(sar:antennaLookDirection)}",
        "sat:orbit_state": "$${strToLowerCase(eop:orbitDirection)}",
        "sat:absolute_orbit": "${eop:orbitNumber}",
        "sat:anx_datetime": "${eop:startTimeFromAscendingNode}"
        // eoCompletionTimeFromAscendingNode?
      },
      "collection": "${eop:parentIdentifier}",
      "assets": "${assets}",
      "links": [
        {
          "href": "$${serviceLink('ogc/stac/v1/collections/%s', eop:parentIdentifier)}",
          "rel": "collection",
          "type": "application/json"
        },
        {
          "href": "$${serviceLink('ogc/stac/v1')}",
          "rel": "root",
          "type": "application/json"
        },
        {
          "href": "$${serviceLink('ogc/stac/v1/collections/%s/items/%s', eop:parentIdentifier, eop:identifier)}",
          "rel": "self",
          "type": "application/geo+json"
        }
      ]
    }
  ]
}